In 1965, Wright reported the first synthesis of 1H-2,1,3-benzothiadiazine-2,2-dioxides from the reaction of sulfamide with 2-aminobenzophenones and 2-aminoacetophenones. Catalytic hydrogenation of the 1H-2,1,3-benzothiadiazine-2,2-dioxides in acetic acid solution using Adams catalyst gave the 3,4-dihydroderivative; Wright, J. B., J. Org. Chem. 1965, 30, 3960. 1H-2,1,3-benzothiadiazine-3,4-dihydro-2,2-dioxides have also been prepared from the reaction of 2-aminobenzylamines with either sulfuryl chloride (Knollmuller, M., Monatsh. Chem. 1970, 101, 1443) or with sulfamide (Houlihan, William J. U.S. Patent 3,278,532, 1966 and (Knollmuller, M., Monatsh. Chem. 1971, 102, 1055).